Recently, in consideration of environmental problems, non-halogen resin compositions in which a red-phosphorus flame retardant is blended with a non-halogen resin are used as flame-retarded resin compositions (Patent Literature 1). Consequently, the development of a method for analysis of red phosphorus useful for quality control in producing and shipping a product containing a red-phosphorus flame retardant, an acceptance inspection for purchasers of the product, and the like has been desired.
Red phosphorus is not dissolved in various types of solvents, and thus it is difficult to separate and collect red phosphorus. In addition, red phosphorus itself has no infrared absorption in an infrared spectrometer. Even when red phosphorus blended in a resin is analyzed using a Raman spectrometer, information about red phosphorus cannot be distinguished from the results. Furthermore, by an elemental analysis, for example, energy-dispersive X-ray (EDX) elemental analysis using an energy-dispersive X-ray fluorescence analyzer, discrimination between red phosphorus and organic phosphorus cannot be performed. Accordingly, in the case where organic phosphorus such as a phosphate ester may be contained, it is impossible to analyze red phosphorus only. Thus, red phosphorus contained in a resin cannot be analyzed by any of these methods.
Consequently, the inventor of the present invention developed, as a method for simply, rapidly, and reliably analyzing red phosphorus, in particular, red phosphorus contained in a resin as a flame retardant, a method in which a sample is gasified with a pyrolysis-gas chromatograph, and a measurement is then performed by gas chromatography, and furthermore, a mass spectrometer is used as means for detecting fractions of the gas chromatography, that is, an analytical method by pyrolysis-gas chromatography/mass spectrometry (pyrolysis-GC/MS), and proposed the method as Japanese Patent Application No. 2007-326840.